IE 11 production build throws error

[tomgenoni]

Possibly related #230

Error shown in console: https://reactjs.org/docs/error-decoder.html/?invariant=31&args%5B%5D=object%20with%20keys%20%7B%24%24typeof%2C%20type%2C%20key%2C%20ref%2C%20props%2C%20_owner%7D&args%5B%5D=

This error is intermittent. Took me a couple tries on production to trigger it. Wasn't able to run locally through Browserstack for some reason to debug further. Renders a blank page.

cc: @mattybow

[mattybow]

Not sure if it is related but the toggle buttons that expand the sections on the left do not do anything

[tomgenoni]

I'm able to reproduce it regularly now. Page renders but error shows up in the console. Our Image examples don't load so it is preventing some code from firing.